The present invention relates to steering columns and more particular to steering columns for motor vehicles which are separable in the event of impact.
When a motor vehicle is subjected to a front impact, the steering wheel carried by the steering column has a tendency to be displaced in the passenger compartment of the vehicle toward the driver.
In order to avoid this displacement of the steering wheel which is dangerous for the driver, various arrangements have been proposed.
For this purpose, steering columns have been constructed in which a part is formed by a corrugated tube capable of being deformed under the effect of an impact by compression of the corrugations.
The drawbacks of such an arrangement is that it has an appreciable residual length, even when the corrugations of the tube have been compressed to the extent of becoming adjoining.
An attempt has also been made to employ telescopic devices comprising a shaft movable in a tube, the retraction force being obtained by the friction of the shaft in the tube either directly by metal-to-metal contact or through an insert of plastics material interposed between the shaft and the tube.
The telescopic device also has the drawback of having a residual length equal to the length of the tube when the shaft is completely engaged in the latter.
It has also been thought of to employ a steering column having a part which is deformable under the effect of impact from the front.
In this arrangement, there is a problem of residual length of the column which allows a certain risk of rearward movement of the steering wheel.
It has also been proposed to render the steering column separable in the event of impact.
For this purpose, two sections of a steering column have been connected by two flanges each carried by a section and interconnected by two shafts rendered integral with one of the flanges and axially slidably mounted in orifices provided in the other flange.